Raghuram Rajan got it started. On Jan. 15, the governor of the Reserve Bank of India jolted traders on Mumbai’s Dalal Street by cutting interest rates. The surprise was the timing of the announcement: Rajan wasn’t supposed to deliver a policy statement for another 19 days.The weirdness continued that same day—in Switzerland, of all places. For three years, the Swiss National Bank had steadily bought euros on currency markets to keep the country’s franc from surging in value relative to the euro, and thereby choking off growth. Unorthodox, yes; but global financial markets had grown accustomed to the regular renewal of the bank’s stance. Without warning, however, the Swiss cut the franc’s tether. Swiss National Bank chairman Thomas Jordan also set the benchmark Swiss lending rate at negative 0.75%. In theory, a lower rate should put downward pressure on the franc; not enough in this case, as the franc’s value shot up by 18% in the days that followed. Many hedge funds bled red.

And on it went. The Danes cut interest rates four times in the span of a few weeks. As this issue of the magazine neared deadline, China’s central bank cut rates by a quarter of a percentage point and Poland slashed them by a half point. In the first 60 days of 2015, some 20 central banks had executed stimulus measures.Let’s call it the Great Central Bank Freak-Out of 2015.The scale and breadth of intervention is reminiscent of the central bankers’ manoeuvres during the 2008-09 financial crisis, with one big difference: There is no obvious emergency this time.